JPS62224765A - Speed change shock reducing device for automatic transmission - Google Patents

Abstract

PURPOSE:To enable execution of processing by means of a digital circuit delayed in computation processing, by a method wherein a feed pressure on a friction element is controlled by three variation characteristics in response to the starting of fastening of the friction element detected during a change in output shaft torque and at each point of time when a minimum or a maximum point is produced. CONSTITUTION:Where an operating condition needs speed change, a change in the reference pressure of a feed fluid pressure is determined during a time ending with a fastening starting point of time tS of a friction element. Right after the starting of speed change, a pressure data PF is outputted as a pressure instruction value P to a circuit 31 to feed a fluid pressure to the friction element, and the fluid pressure is controlled according to first change characteristics. When a fastening starting point of time tS is detected, the data PF is varied into data decided by second change characteristics, and the changed data is divided into data in plural cases according to a kind of speed change and an operating condition to reduce pressure data. After a point of time tB lapses when a minimum point is produced, data is varied into decision data of third change characteristics to gradually increase a feed pressure. After transmission motion is completed, a difference in torque between a minimum point tB and a maximum point tF forms a fluctuation width DELTATOUT to decide the quality of speed change motion.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is applicable to automatic transmissions for vehicles, and particularly relates to a shift shock reduction device for automatic transmissions that can reduce shift shock. Regarding.

(Prior Art) Conventional gear shift shock reduction devices for automatic transmissions include, for example, Japanese Patent Application Laid-Open No. 52-106064 and Japanese Patent Application Laid-open No. 53-85.
There is one described in No. 264.

The conventional device described above detects the output shaft torque of an automatic transmission with a torque sensor, and changes gears while feeding back a detection signal of the output shaft torque so that the output shaft torque changes in accordance with a preset torque change. The aim is to reduce shift shock by controlling the fluid pressure of the hydraulic friction elements used in the transmission.

(Problem to be Solved by the Invention) However, the above conventional device detects the output shaft torque of the automatic transmission with a torque sensor, feeds back this detection signal, and sets the actual change in the output shaft torque in advance. Since the configuration is such that real-time control is performed in accordance with the torque changes, if the control is performed using a digital calculation circuit such as a microcomputer, an expensive device capable of high-speed calculation is required.

Furthermore, due to the real-time control described above, if error components such as noise are mixed into the torque sensor output, the control accuracy will immediately decrease.To prevent this, it is necessary to use a highly accurate torque sensor, i.e. An expensive torque sensor is required.

(Means for Solving the Problems) In order to solve the above problems, the present invention includes means shown in FIG.

Torque sensor 101 detects output shaft torque of automatic transmission 100.

The engagement start time detection means 102 detects the start time of engagement of the fluid pressure type friction element 111 for shifting that constitutes the automatic transmission 100 during shifting, based on the fluctuation waveform of the output shaft torque detected by the torque sensor 101. .

The minimum point detection means 103 first detects the occurrence point of a minimum point at which the change in the output shaft torque reverses from decrease to increase after the time point at which the engagement of the friction element starts is detected.

The timer means 104 measures a predetermined time limit from the time when the friction element starts to be fastened.

The maximum point detection means 105 first detects the time point at which a maximum point occurs at which the change in the output shaft torque reverses from increase to decrease after the time point at which the engagement of the friction element starts is detected.

The first supply pressure control means 107 increases the supply pressure to the friction element 111 according to a preset first change characteristic from the start of the shift operation of the automatic transmission to the start of the engagement. let

The second supply pressure control means 108 controls the friction element 111 according to a preset second change characteristic from the start of the engagement to the time when the minimum point occurs or the time limit, whichever comes first. Reduce the supply pressure to.

The third supply pressure control means 109 controls a preset third supply pressure from the time when the minimum point occurs until the end of the shift operation.
The supply pressure to the friction element 111 is increased according to the change characteristics of the friction element 111.

The quality determining means 106 is based on the change in the output shaft torque during the shift operation period, the output shaft torque at each time of the engagement start time, the minimum point occurrence time, the local maximum point occurrence time, or the change time of the output shaft torque. , determines whether the gear shifting operation is good or bad.

The change characteristic modifying means 110 adjusts the first to third characteristics based on at least the determination result by the quality determining means 106.
Modify at least one of the change characteristics of.

(Operation) The present invention detects significant change points among changes in output shaft torque, such as the time when the friction element starts to engage, the time when a minimum point occurs, and the time when a maximum point occurs, and detects when these change points arrive. Correspondingly, by controlling the supply pressure to the fluid pressure friction element 111 according to the first to third change characteristics, the detected value of the output shaft torque is fed back in real time unlike the conventional device, and the preset value is This can be achieved using a digital circuit that requires slower calculation processing time than those that compare torque changes.

In addition, even if error components such as noise are mixed into the detection signal of the torque sensor 101, it has little effect on the detection of the above-mentioned significant change points, so there is no need to use a high-precision torque sensor, reducing costs. can be achieved.

Furthermore, the first to third supply pressure control means 107 to 109 switch the supply pressure control to the friction element 111 to an appropriate change characteristic in accordance with the occurrence of the remarkable change point, and The quality determining means 106 determines whether the gear shifting operation is good or bad, and the change characteristics of the supply pressure are corrected according to the result of this determination, thereby eliminating individual differences in automatic transmissions and friction coefficients of friction elements. Appropriate supply pressure can be applied in response to changes in speed change operation characteristics due to changes over time or the like.

(Example) The configuration of the first embodiment of the present invention is shown in FIG.

The control circuit 2OA is mainly composed of a digital arithmetic circuit constructed using a microcomputer or other digital circuit. In the figure, some functional blocks are shown to make the control functions easier to understand.

The information input to the control circuit 20^ is the torque sensor,
Output shaft torque T of automatic transmission (path shown) detected at 0
. UT and the throttle opening detected by the throttle opening sensor 11 5T14. and the rotation speed N of the output shaft of the automatic transmission detected by the output shaft rotation speed sensor 12. It is ut.

The torque sensor 10 is a well-known magnetostrictive torque sensor (similar to the one described in the above-mentioned conventional publication), and the output signal is an analog signal, so the control circuit 20
The signal is converted into a digital signal by an A/D converter 30 within the unit. The output signals of the throttle opening sensor 11 and the output shaft rotation speed sensor 12 are digital signals.

The output signal outputted from the control circuit 20^ is a drive signal for a pressure control valve 4o that controls the fluid pressure of a hydraulic friction element for shifting that constitutes an auxiliary transmission mechanism of the automatic transmission.

As shown in FIG. 3, the pressure control valve 40 is composed of a spool valve 51 and a solenoid valve 52, and controls the supply pressure PL (which is the output pressure from the oil pump) supplied to the input oil path 55. The variable orifice 53 whose opening degree is adjusted by the fixed orifice 53 and the solenoid valve 52 applies control pressure PC to the spool valve 51 to adjust the amount of displacement of the spool 51S, and as a result, the output from the output oil path 56 The pressure P is adjusted. The output oil passage 56 is connected to the hydraulic oil supply passage of the front hydraulic friction element.

The drive signal I given to the pressure control valve 40 from the control circuit 20A is the excitation current of the solenoid pulp 52, and this drive signal! is P in the control circuit 20
This is a pulse width modulated current signal output from the WM circuit (pulse width modulation circuit) 31.

That is, by changing the ON/OFF duty ratio of the drive signal (2) using the PWM circuit 31, the amount of displacement of the spool 52S of the solenoid valve 52 is adjusted, and the opening degree of the variable orifice 54 is adjusted. As a result, the output pressure P is adjusted.

The control circuit 2OA receives each of the above input information T. LIT+S
? Based on ll+N0IJr, the hydraulic pressure to be applied to the hydraulic friction element for gear shifting is determined and control is performed to reduce gear shifting shock.The functional structure thereof is shown in FIG. 2 by a functional section 21. ~28.

The shift point determining unit 21 determines the throttle opening degree SA, 1 and the output shaft rotation speed N. The gear position of the automatic transmission is determined based on Ua.

When the gear position is determined by the shift point determining section 21, the pressure determining section 22 recognizes a change in the gear position, that is, when a shift is performed, and activates a hydraulic friction element for shifting during this shift. Preset the change in supply pressure to (
This change in the set supply pressure is referred to as the "reference pressure change").

The waveform recognition unit 24 detects the output shaft torque T. Enter uT,
A time point t8 when the engagement of the friction element starts during gear shifting; a time point t when a minimum point occurs at which the direction of change in the output shaft torque tou'r first reverses from decrease to increase after this engagement start time has elapsed;
% and detection of the point in time tp at which the maximum point at which the direction of change in the output shaft torque 'rou↑ first reverses from increase to decrease;
and the value of the output shaft torque at each of these points, and
From time t, to t.

(hereinafter referred to as "transition time Lα").

The quality determination unit 25 determines the fluctuation range ΔTO of the output shaft torque during gear shifting from the value of the output shaft torque measured by the waveform recognition unit 24.
UT is determined, and from the magnitude of this variation range ΔTOLIT and the length of the transition time tα, it is determined that when one gear shift is performed, the shift operation will not cause a sudden change in acceleration that may cause discomfort to the driver. It is determined whether or not such large torque fluctuations have occurred, and whether or not the time required for the gear shifting operation is an appropriate length.

The storage unit 26 is a memory, and is configured to determine the correction amount ΔP of the supply pressure to the friction element and the allowable shift time Jc in consideration of the wear resistance of the friction element, depending on the type of shift and operating conditions. Preset data is stored as a data table.

The pressure change correction unit 23 determines the pressure to be supplied to the friction element to be applied during gear shifting, based on the reference pressure change set by the pressure determination unit 22 and the pressure correction amount ΔP.

The timer 28 starts a timing operation in response to the waveform recognition unit 24 detecting the time point t when the engagement of the friction element starts, and measures a preset time limit t,4.

The pressure control unit 27 uses the waveform recognition unit 24 to determine the time point at which fastening starts [
5. Generate an output for forming the drive signal I to be applied to the pressure control valve 40 each time the minimum point occurrence time t8 is detected or when the time limit 1 is counted by the timer 28. This output is determined based on the corrected reference pressure change given by the pressure change correction section 23.

Further, the pressure control section 27 corrects the data in the storage section 26 in accordance with the result of the judgment by the quality judgment section 25 as to whether the speed change operation is good or bad.

Next, FIGS. 4 to 6 show the control circuit 2OA when the control circuit 2OA is configured using a microphone computer.
It is a flowchart which shows the process performed at 0A. The processes shown in FIGS. 4 to 6 are a series of processes, and are repeatedly executed at predetermined time intervals.

In the process of step 61 in FIG. 4, the throttle opening ST
H and output shaft rotation speed N. Each input data of the UT is read.

In step 62', the content of the flag F for determining the control mode is determined, and it is determined which routine to proceed to thereafter. This flag F is set with 2-bit data and is “00
” indicates that the gear is not shifting, “01” indicates that the gear is shifting, and rlOJ indicates that the shift operation is being determined. Note that when the ignition switch is turned on, the flag F is reset to "00".

If the flag F=00 is determined as a result of the determination in step 62, then the operating conditions are determined in the process of step 63, and the shift diagram stored in advance in the memory is updated in the process of step 64. Based on the above operating conditions (
Throttle opening S□ and output shaft rotation speed N0Ij? (determined by ) exceeds a shift point that requires a shift.

Here, if the driving conditions are not such that shifting is required,
Exit the routine without taking any control. On the other hand, if a shift is required, steps 66 to 69 are executed.

In step 66, a data table storing a first change characteristic (hereinafter referred to as a "first change characteristic table") is selected from a data table of pressure data stored in the memory (hereinafter referred to as a "pressure data table"). ), and by lookup processing of this first change characteristic data table, a reference pressure change in the fluid pressure supplied to the friction element is determined until the friction element engagement start point ( , which will be described later).

The above pressure data table shows the type of speed change (for example, “1
There are multiple cases depending on the operating conditions (throttle opening STM, output shaft rotation speed N.u7, vehicle speed, etc.). The reference pressure PF under each condition is stored.

In the next step 67, the reference obtained in step 66 is performed by lookup processing of a data table of correction amount data for the first change characteristic (hereinafter referred to as "first correction amount data table") stored in the memory. Pressure PF
A correction amount ΔP1 (one time correction amount) is determined, and the reference pressure P is corrected by this correction amount ΔP1.

Then, in the next step, day 6, the flag F is set to "01" to remember that the shift operation has started.

Since the flag F=10, the process of step 70 in FIG. 5 is thereafter performed. In this step 70,
Activate the A/D converter 30 to obtain the output shaft torque T. Reads data from Ua.

Then, in the next step 71, the output shaft torque T is read every time the routine process is executed. U? By comparing the magnitudes of, the friction element engagement start time ts and
Output shaft torque T at this point.

After time t and time t are detected, time 1 of the minimum point at which the direction of change of the output shaft torque first reverses from decrease to increase, output shaft torque T1 at this time, and time t are detected. The time point t when the maximum point at which the direction of change in the output shaft torque is reversed from increase to decrease, the output shaft torque T7 at this time point, and the transition time tα required from the time point t to t. demand.

In the process of the next step 72, it is determined from the content of the flag FA whether or not the time point t, when the engagement of the friction element starts has elapsed.

Now, at time t0 in FIG. 7, the determination in step 65 is YES.
Assume that the shift operation is started.

Immediately after the shift starts, the flag is FA・00, and the flag FB, which will be described later, is also roOJ.
In the process of step 79, the pressure data P2 determined in step 67 is outputted as the pressure command value P to the PWM circuit 31. As a result, a fluid pressure equal to the pressure data PF is supplied to the friction element.

The liquid pressure at this time will be controlled according to the first change characteristic (however, correction has been made in step 67).

In step 81, the time point t when the friction element starts to be fastened.

Processing to detect is being carried out. This is shown in Figure 7(a)
This is a process of detecting point A in the center. When this point A occurs, the friction element has started to engage and the clutch plate has started to be pressed, so the output shaft torque has increased due to load fluctuations due to inertia components, etc. T. This is the point at which uT begins to drop rapidly.

The detection of this fastening start time t is based on the output shaft torque T read in step 70 above. Compare uT with the output shaft torque read in the previous process, and obtain the output shaft torque T for a predetermined number of consecutive times. When UT decreases and the amount of decrease in the output shaft torque during this period is equal to or greater than a predetermined value, the process is performed to determine that it is the time to start the engagement.

When the fastening start point is detected, the pressure data P that has been according to the first change characteristic is changed by the process of step 82.
" is changed to pressure data determined according to the second change characteristic.

The second change characteristic is stored in the memory as a data table (hereinafter referred to as “second change characteristic”).
It is stored as a "change characteristic table"), and is divided into multiple cases depending on the type of shift and driving conditions.

Then, in step 83, a flag FA, 01 is set to indicate that the time at which the fastening was started has elapsed, and in step 84, a timer is started. This timer starts at time 1.
A preset time limit from 1. It is used to measure the time.

Through the processing up to this point, the duty ratio of the drive signal ■ up to the time point to-tg becomes the duty ratio for generating pressure data according to the first change characteristic, as shown by the broken line in FIG. 7(c). , the supply pressure to the friction element begins to rise after a slight time delay t4, as shown in FIG. 7(b).

Then, when time t has passed, the duty ratio for generating pressure data based on the second change characteristic is reached, and the supply pressure to the friction element is changed as shown by the broken line PI in FIG. 7(b). , decreases by a predetermined amount from time ts. That is, the second change characteristic is a characteristic that reduces the pressure data.

When the fastening start time t has elapsed, the flag becomes F^.01, so the determination in step 72 becomes YES, and in the process of the next step 73, from the contents of the flag FB, the occurrence time t of the minimum point, Determine whether or not the period has elapsed.

If the flag is FB-00, the minimum point is detected in step 85. In this process, step 70
Output shaft torque T read in. The magnitude relationship between u7 and the output shaft torque read in the previous process is determined, and when the output shaft torque changes from repeating a monotonic decrease to a monotonous increase, it is determined that the minimum point occurs at the time t3. Processing takes place.

This minimum point occurrence point t is a displacement point when the output shaft torque at a new gear ratio is reached after the engagement start time t, as shown in point B shown in FIG. 7(a). From this minimum point B onwards, the output shaft 1-lux begins to increase because inertial energy due to rotation is released due to a decrease in engine output rotation speed due to a decrease in gear ratio.

When the minimum point occurrence time point t has elapsed, the pressure data that has been according to the second change characteristic is changed to the pressure data determined according to the third change characteristic by the process of step 87.

The third change characteristic is stored in the memory as a data table (hereinafter referred to as the "third change characteristic table"), and there are multiple cases depending on the type of speed change and operating conditions. being done.

This third change characteristic is a characteristic that gradually increases the supply pressure to the friction element after the minimum point occurs, and step 87
Then, the initial value of the pressure data at the start of this gradual increase is determined.

By the way, after the start of the speed change operation, the time point t when the engagement of the friction element starts
, the supply pressure to the friction element is reduced.
At this time, due to individual differences in automatic transmissions, changes in the friction coefficient of the friction elements over time, etc., as the supply pressure decreases, the engagement pressure of the friction elements may become too weak, resulting in poor gear shifting operation. .

When such a situation occurs, if no action is taken,
Minimum point B does not occur, and the supply pressure remains reduced.

Therefore, by the process of step 86, the step 84
It is determined whether or not the time limit tx has elapsed by determining the timing content of the timer started.

Therefore, if the minimum point B is not detected even after the time limit t6 has elapsed, step 87 is performed after the time limit L has elapsed to increase the supply pressure, thereby preventing a shift operation failure. can be prevented.

In addition to setting the above-mentioned time limit 1 as a constant value, the time corresponding to the occurrence time of the above-mentioned minimum point is set according to each driving condition and type of shift, and the set time data for each of these conditions is It is also possible to store it in memory as a data table.

After the process in step 87 is executed, in step 88, the flag FB.Ol is set to store that the minimum point occurrence time t8 has passed. Then, in step 89, the timer is reset.

As a result, at time t, the duty ratio of the drive signal (2) becomes the duty ratio for outputting the pressure data determined by the third change characteristic, and the supply pressure to the friction element starts to rise.

When the local minimum point occurrence point [, has elapsed, the determination of the steering knob 73 becomes YIES, and then, in the process of step 74, a small amount of the pressure data determined in the above step 87 (
1 step) is performed.

Then, in step 75, the required shift time 9 is determined, that is,
The elapsed time from the above-mentioned engagement start time t3 is measured, and in step 76, the shift operation is terminated depending on whether or not the required shift time J has reached the allowable shift time Jc stored in the memory. Determine whether or not it was done.

Therefore, the process of step 74 is repeated until it is determined that the shift operation has ended, and the pressure data increases by one step each time. As a result, the drive signal I
The duty ratio gradually increases after the minimum point occurrence time t until the shift end time t, and accordingly, the supply pressure to the friction element also gradually increases.

When the speed change operation is completed, the process of step 77 is performed to change the pressure data to data for bringing the friction elements into a fully engaged state. That is, a pressure command value P that makes the duty ratio of the drive signal I 100% is output.

This completes the gear shifting operation, and in step 78, the flag F is reset to rlOJ and the flags F^ and FB are reset to "00".

Since the flag F=10, the processes of steps 91 to 95 in FIG. 6 are performed thereafter.

In the process of step 91, it is determined whether the shift operation performed in the current routine process was successfully performed without causing a shift shock.

Here, the output shaft torque at the time point t when the minimum point occurs (hereinafter referred to as "first minimum point torque") Ts and the output shaft torque at the time point t when the maximum point occurs (hereinafter referred to as "the first Maximum point torque) T
A process is performed in which the difference from P (TP-TI) is determined and this is set as the fluctuation range Δtoor of the output shaft torque. Then, the fluctuation range ΔTouT and the transition time t obtained in step 71
The quality of the gear shifting operation is determined based on whether or not α is less than or equal to a predetermined value.

This means that when the fluctuation width Δ'rotoT is large, the output shaft torque T. This is used as a criterion because the shift shock associated with uT fluctuations becomes large.

Furthermore, regarding the transition time tα, if the degree of increase in the fluid pressure supplied to the friction element according to the first change characteristic is too small, the transition time becomes long, and it can be determined that the speed change operation was not as desired. Furthermore, when the transition time tα is short, rapid fluctuations in the output shaft torque tend to occur, so the above fluctuation range Δ'rout also becomes large, and both tα and ΔTon indicate that the gear shifting operation is not performed well. becomes clear.

Here, if it is determined that the gear shifting operation has not been performed satisfactorily, the determination at step 92 becomes No, and step 9
In step 3, a pressure correction amount ΔPI for correcting the first change characteristic is calculated.

This pressure correction amount ΔPI takes a value that reduces the supply pressure to the friction element when the fluctuation width ΔTOUT is too large, and takes a value that increases the supply pressure when the transition time tα is too long.

This pressure correction amount ΔPl is replaced with existing data in the first correction amount data table used in step 67 at a position corresponding to the operating conditions and type of speed change during the current speed change operation.

As a result, the next time a shift operation is performed under the same conditions as this time, the pressure data determined according to the first change characteristic is corrected by the changed first correction amount ΔPI, thereby reducing the shift shock. Fluid pressure adjusted in the direction of the friction element is supplied to the friction element.

On the other hand, if it is determined that the current shift operation was performed well, the pressure supplied to the friction element was at an appropriate value, and therefore the pressure correction amount is not changed.

Then, in step 95, since the routine processing has ended, processing for resetting the flag F is performed.

Through the above processing, the output shaft torque T during shifting. The change in uT is as shown by the broken line T in FIG. 7(a). The change indicated by the solid line T in the same figure is the change indicated by the solid line T in Fig. 7(c).
As shown by loz, this is the output shaft torque change when the duty ratio is kept constant during the gear shifting operation.

When the duty ratio is kept constant, the supply pressure becomes constant as shown by the solid line P2 in FIG. 7(b) from the time t when the friction element starts to be engaged, so that the output shaft torque T. 0
The rate of change and width of change in A are larger than in this embodiment.

In contrast, in this embodiment, the supply pressure is once reduced at the fastening start time t3 to weaken the fastening force at the minimum point B, and the fastening force at the minimum point B is reduced.
Thereafter, by gradually increasing the supply pressure, the fluctuation width Δtour of the output shaft torque can be significantly reduced, and the occurrence of shift shock can be prevented.

Note that the reason why the supply pressure is once greatly increased at time t is to improve the responsiveness of the supply pressure increasing operation. By doing this, even if the output shaft torque decreases at time t0, it will be a value determined by the product of the gear ratio and the input torque of the automatic transmission, and from then on, the output shaft torque will decrease due to the release of inertial energy again. Although there is an increase, since the fastening force of the friction element is weakened, it is a gradual increase, and the change in the output shaft torque does not become as large as at point R.

Next, a second embodiment of the present invention will be described.

The hardware configuration of this embodiment is the same as that of the first embodiment, as shown in FIG. The control valve 40 is configured as an input/output device. Therefore, FIG. 2 is also used as a configuration diagram of this embodiment.

The processing executed by the control circuit 20A is slightly different between the first embodiment and this embodiment.

8 and 9 are flowcharts showing a part of the processing executed in this embodiment. The difference from the processing in the first embodiment is that after step 87 in FIG. Step 201 is provided as shown in FIG. 6, and steps 204 and 20 are provided after steps 93 and 94 in FIG.
5 (shown in FIG. 9), and in place of step 71 in FIG. 5 and step 91 in FIG. 6, steps 202 and 203 were provided to perform processing different from these. It is.

Note that the processing in steps 61 to 69 shown in FIG.
This is also executed in this embodiment.

In step 202, the output shaft torque T at the friction element engagement start time t3 obtained in step 71 in the first embodiment, the first minimum point torque TB%, the first maximum point torque Tp, and the transition time [ In addition to α, as shown by points Q and P in FIG. 7(a), after the maximum point P occurs, the output shaft torque T. The point at which LIT reverses from decreasing to increasing (hereinafter referred to as "second minimum point occurrence point") t
output shaft torque at o (hereinafter referred to as “second minimum point torque To
J) and the output shaft torque (hereinafter referred to as "second maximum point torque T") at the time b when the direction of change of the output shaft torque reverses from increase to decrease (hereinafter referred to as "second maximum point occurrence time").
, J), and from time point L0 to 1. 1 (hereinafter referred to as "second transition time [β")].

In step 201, the pressure data determined in step 87 is corrected by adding a pressure correction amount ΔP for correcting the third change characteristic obtained from the third correction amount data table.

In step 203, in addition to the process of determining the quality of the shift operation based on the variation width Δrout of the output shaft torque and the transition time tα performed in step 91 in the first embodiment, the second minimum point torque T0 obtained in step 202 is added. and the second local maximum point torque TII (=1°-To, hereinafter referred to as the second fluctuation range ΔTouTzJ), and the second fluctuation range ΔTOLI72 and the second transition time tβ are calculated as follows. The quality of the gear shifting operation is also determined based on whether or not the value is below a predetermined value.

Then, the above ΔTouT+ Lα, ΔToutz +
When it is determined that the gear shifting operation was not good in any of the determinations for tβ, step 9
Processes 3, 94, 204, and 205 are performed.

The process of step 204 is a process of determining the third pressure correction amount ΔP3 according to the magnitude and length of ΔTOUT□ and tβ.

In step 205, the pressure correction amount ΔP1 calculated above is
is stored in the third correction amount data table used in step 201 at a position corresponding to the same operating conditions and type as the current speed change.

The third pressure correction amount ΔP is determined as follows.

Output shaft torque T during gear shifting. u7 changes as shown by the broken line T in FIG. 7(a).

Here, if the degree of increase in the supply pressure from the minimum point occurrence point ts is too slow, the engagement action of the friction element becomes slow, resulting in a delay in reaching a new gear ratio, and during this time, a state in which torque is not sufficiently transmitted occurs. do.

Therefore, the second minimum point torque T. drops, then
As the output shaft torque increases, albeit slowly, the engagement force of the g-friction element becomes stronger, and the shift operation progresses until reaching the second maximum point R.
occurs, but because the rate of increase in supply pressure is low,
The second transition time tβ between time points t0 and te becomes longer.

Conversely, if the rate of increase in the supply pressure from time t is too high, the second transition time tβ becomes short and the difference between the second minimum point torque T0 and the second maximum point torque T8 (i.e., the second The fluctuation width ΔTO1l?□) becomes large.

Therefore, the third pressure correction amount ΔP is the second fluctuation range ΔT
When outz is too large, the value is set to decrease the supply pressure (according to the third change characteristic), and when the second transition time tβ is too long, the value is set to increase the supply pressure.

As described above, in this embodiment, by adjusting the supply pressure to the friction element after the maximum point occurrence point t (correcting the third change characteristic), a better gear shifting operation can be performed.

In particular, by correcting the first change characteristic, the fluctuation range ΔT0
, 7 can be suppressed, the magnitude of the second fluctuation range ΔT0υTz can no longer be ignored (Δ'root
(The ratio of ToL+72 becomes large), it is effective to perform the correction of the third change characteristic at the same time as described above.

Next, a third embodiment of the present invention will be described.

The hardware configuration of this embodiment is the same as that of the first embodiment, as shown in FIG. The control valve 40 is configured as an input/output device. Therefore, FIG. 2 is also used as a configuration diagram of this embodiment.

The processing executed by the control circuit 208 is slightly different between the first embodiment and this embodiment.

That is, as shown in FIG. 10, step 8
7 or steps 211 and 212.

Note that steps 61 to 6 shown in FIGS. 4 and 6
9 and steps 91 to 95 are similarly executed in this embodiment.

In this embodiment, the time limit 1. is measured by a timer after the speed change operation is started and the friction element engagement start time t has elapsed. When the minimum point occurrence time point t is detected within this time, steps 87 to 89 are executed, and the supply pressure to the friction element starts to gradually increase based on the pressure data determined according to the third change characteristic.

On the other hand, the minimum point occurs within the time limit t0.

is not detected, the time limit 1. At the point in time (this point is defined as r tt J), step 7 step
Processes 1, 212, 88, and 89 are performed.

That is, in step 211, similar to step 87, processing is performed to change the pressure data to data determined by the third change characteristic.

Then, in step 212, the pressure data after the change is further corrected. This pressure data correction is performed using a third correction amount ΔP3 obtained from a third correction amount data table configured of data for correcting the third change characteristic stored in advance in the memory.

As a result, the initial pressure at the time when the supply pressure to the friction element starts to gradually increase is controlled to a value higher than the initial pressure when the minimum point occurrence point i is detected.

The reason for performing such control will be explained below.

As shown in FIG. 11, control is performed so that the supply pressure to the friction element is reduced by a predetermined amount after the friction element engagement start time ts has elapsed.

If the amount of decrease in the supply pressure at this time is appropriate, a minimum point B will occur as the gear ratio changes, and the output shaft torque T will decrease. ut changes as shown by the solid line ↑1 in FIG. 11(a).

On the other hand, if the reduction in the supply pressure after the fastening start time ts is excessive and the undercut point B does not occur, the pressure data based on the third change characteristic (by the correction amount ΔP3) is (with corrections made) a gradual increase in the supply pressure is performed.

At this time, as shown by the dashed line T in FIG. 11(a), the time point 11 at which the time limit tM has elapsed is usually later than the time point t8 when the minimum point occurs, so the time point 11 is indicated by a point B'' in the figure. Thus, the output shaft torque at time 1T is smaller than the output shaft torque at time t.

Therefore, if the supply pressure to the friction element is gradually increased from time point 11 using the third change characteristic without correction, the supply pressure will start increasing from a fairly low level and will not reach the shift end time point t1. It is conceivable that a situation may arise in which the supply pressure does not rise to a sufficient level.

Therefore, when the friction elements are brought into a fully engaged state at the end of the gear shift operation, excessive residual energy remains.
There is a risk of sudden torque fluctuations.

Therefore, as in this embodiment, when the supply pressure to the friction element is gradually increased from the point 11 after the time limit 1 has elapsed, the initial value of the supply pressure at the start of the gradual increase is increased by the amount that the supply pressure has decreased too much. increase.

That is, by the processing of steps 211 and 212,
By correcting the pressure data, the duty ratio of the drive signal I at time 11 becomes larger than the duty ratio at time ts, as shown by the dashed line D3 in FIG. 11(c).

From then on, D3 and paste will gradually increase at the same rate of increase, but since D has a higher initial value, the supply pressure to the friction element will also increase accordingly.

The change in the supply pressure to the friction element at this time is shown in Figure 1(b).
It becomes as shown by the dashed line P in the middle. Also, the output shaft torque T. II? The change in is shown by the dashed line T3 in FIG.

As shown by this change characteristic T, the minimum point,
Although the timing of the occurrence of the maximum point is delayed, the width of fluctuation is suppressed to a small extent, and torque fluctuations due to residual energy do not occur.

It should be noted that if control is performed in combination with the present embodiment and the second embodiment described above, even more appropriate control of the speed change operation can be performed.

(Effects of the Invention) As described above in detail, the present invention provides a method for detecting significant changes in the output shaft torque, such as when the friction element starts to engage, when the minimum point occurs, and when the maximum point occurs. By detecting the change points and controlling the supply pressure to the fluid pressure friction element according to the first to third change characteristics in response to the arrival of these change points, output shaft torque can be detected in real time unlike conventional devices. This can be realized using a digital circuit that requires slower calculation processing time than a system that feeds back the value and compares it with a preset torque change.

Additionally, even if error components such as noise are mixed into the torque sensor's detection signal, it will have little effect on the detection of the above-mentioned significant change points, eliminating the need for a high-precision torque sensor and reducing costs. .

Furthermore, the present invention provides that the supply pressure control to the friction element is switched to an appropriate change characteristic in accordance with the occurrence of the remarkable change point, and the value of the output shaft torque at the remarkable change point. By determining whether the gear shifting operation is good or bad based on the change time of output shaft torque, etc., and modifying the change characteristics of the supply pressure according to the results of this determination, individual differences in automatic transmissions and , it is possible to apply an appropriate supply pressure in response to changes in shift operation characteristics due to changes over time in the friction coefficient of the friction element, etc.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of the present invention, FIG. 2 is a block diagram showing the configuration of an embodiment of the present invention, FIG. 3 is a sectional view showing the specific configuration of the pressure control valve in FIG. 2, and FIG. 6 to 6 are flowcharts showing the processing executed by the control circuit in FIG. 2, and FIG. 7 shows the adjustment operation of the supply pressure of the friction element and the fluctuation status of the output shaft torque according to the embodiment shown in FIG. 2. 8 and 9 are flowcharts showing part of the processing executed by the control circuit in the second embodiment of the present invention, and FIG. FIG. 11 is a flowchart showing a part of the processing, and FIG. 11 is a diagram showing the adjustment operation of the supply pressure to the friction element and the change in the output shaft torque according to the third embodiment. 100... Automatic transmission 101... Torque sensor 102... Fastening start point detection means 103... Minimum point detection means 104... Timer means 105... Pilot point detection means 106... Good or bad Discrimination means 107...First supply pressure control means 10B...Second supply pressure control means 109...Third supply pressure control means 110...Change characteristic correction means 111...Fluid pressure friction Element 10... Torque sensor 11... Throttle opening sensor 12... Output shaft rotation speed sensor 20A... Control circuit 40... Pressure control valve TOtl? ... Output shaft torque 1 ... Limit time t
0... Time point t when the speed change operation starts,... Time point j++ when the engagement of the friction element starts,... Time point t when the minimum point occurs,... Time point when the maximum point occurs, to... Time point when the second minimum point occurs,... From the point at which the second maximum point occurs...The point at which the time limit has elapsed Figure 1 Figure 7 Figure 9

Claims (1)

[Scope of Claims] 1. A torque sensor that detects the output shaft torque of an automatic transmission; and a gear shifting device that constitutes the automatic transmission when shifting, based on a fluctuation waveform of the output shaft torque detected by the torque sensor. A fastening start point detecting means for detecting a fastening start point of the hydraulic friction element; and after the fastening start point of the friction element is detected, the change in the output shaft torque is first reversed from decreasing to increasing. a minimum point detection means for detecting the point at which the point occurs; after the point at which the engagement of the frictional element starts is detected, the point at which the change in the output shaft torque first reverses from increase to decrease; detecting the point at which the maximum point occurs; maximum point detection means; timer means for timing a predetermined time limit from the time when the friction element starts to engage; a first supply pressure control means for increasing the supply pressure to the friction element according to a change characteristic of the friction element; and a first supply pressure control means for increasing the supply pressure to the friction element from the time when the engagement starts to the time when the minimum point occurs or the time limit, whichever comes first; a second supply pressure control means for reducing the supply pressure to the friction element according to a second preset change characteristic; a third supply pressure control means for increasing the supply pressure to the friction element according to the change characteristic of the third change characteristic; and a third supply pressure control means for increasing the supply pressure to the friction element according to the change characteristics of the output shaft torque during the shift operation period, and the time when the engagement starts, the time when the minimum point occurs, and the time when the maximum point occurs. quality determining means for determining whether the gear shifting operation is good or bad based on the output shaft torque at each point in time or the change time of the output shaft torque; 1. A shift shock reduction device for an automatic transmission, comprising: change characteristic correction means for correcting at least one change characteristic of the change characteristics. 2. The quality determining means is based on the difference between the output shaft torque at the time when the minimum point occurs and the output shaft torque at the time when the maximum point occurs, and the time from the time when the engagement starts to the time when the minimum point occurs, Claim 1, characterized in that, in addition to determining whether the gear shifting operation is good or bad, the change characteristic modifying means corrects the first change characteristic in accordance with the result of determining whether the gear shifting operation is good or bad. A shift shock reduction device for an automatic transmission described in . 3. After the occurrence of the maximum point, the pass/fail determining means is configured to detect the occurrence of a second minimum point at which the change in output shaft torque reverses from decreasing to increasing, and a second maximum point at which the change in output shaft torque reverses from increasing to decreasing. The change characteristic modifying means determines whether the shift operation is good or bad based on the difference in the output shaft torque of and the time between the two times, and the change characteristic modifying means determines whether the third change is good or bad based on the result of determining whether the shift operation is good or bad. 3. A shift shock reducing device for an automatic transmission according to claim 1 or 2, characterized in that a characteristic is modified. 4. The change characteristic modifying means corrects the third change characteristic depending on which of the minimum point generation time and the time limit arrives first after the detection of the start time of engagement of the friction element. A shift shock reducing device for an automatic transmission according to any one of claims 1 to 3.